George Zimmerman enters the courtroom Wednesday at his trial in Sanford, Fla. / Jacob Langston, AP

by Yamiche Alcindor, USA TODAY

by Yamiche Alcindor, USA TODAY

SANFORD, Fla. - The jury at George Zimmerman's murder trial were told about his rejection letter from a Virginia police department, his course work for a class that discussed self-defense laws, and his application to do a police ride-along, Judge Debra Nelson ruled Wednesday.

"The testimony is substantive," Nelson said, overruling an objection by Zimmerman's lawyer.

Zimmerman, 29, has pleaded not guilty to second-degree murder - claiming self-defense - in the shooting death of Trayvon Martin, 17, last year.

Assistant State Attorney Richard Mantei said the records show Zimmerman had a continuous interest in becoming a police officer, understood police techniques, and understood criminal investigations.

Mark O'Mara, Zimmerman's attorney, said the records were irrelevant and didn't show Zimmerman's state of mind when he shot Trayvon. He called the prosecution effort a "fishing expedition."

With the ruling, the jury will learn that in July 2009 Zimmerman's application to be a Prince William, Va., police officer was rejected, and that in March 2010 he applied for a police ride-along.

The ruling also means the jury will see Zimmerman's homework he did toward an associate's degree in criminal justice. Zimmerman was set to graduate in spring 2012, the jury will learn. They'll also learn that Zimmerman had access to literature about how to "excel as a witness" and the theory behind Florida's stand-your-ground and self-defense law.

"It certainly goes to a state of mind," said Mantei who added that the records show Zimmerman carried wanted to be a police officer.

Alexis Carter, a former Seminole County College professor, testified that Zimmerman earned an 'A' in his criminal litigation class. Carter says he discussed Florida's self-defense and stand-your-ground laws quite often with students.

Zimmerman was among one of his better students, Carter said.

Prosecutors said Carter's testimony is important because Zimmerman told Sean Hannity in an interview that Zimmerman didn't know about stand your ground laws until after shooting Trayvon. Carter told jurors he taught Zimmerman's class about stand your ground and talked extensively about self defense.

The state also called state crime lab analyst Amy Siewert, who examined Zimmerman's gun and found evidence that he carried it loaded and ready to fire. She said law enforcement officers often carry their firearms that way.

Siewert also found evidence that the muzzle of Zimmerman's gun was touching Trayvon's sweatshirt when the fatal shot was fired. When pressed by lawyers, Siewert said she couldn't say whether the gun was pressed or lightly touching the fabric, only that the gun was touching Trayvon's clothing.

The analyst also demonstrated for jurors using Zimmerman's gun how the gun worked and how a person would load the gun. While she did so, jurors eyes were locked on her and taking notes quickly.

Jim Krzenski, a Sanford Police administration service manager, said Zimmerman applied to go on a police ride-along once on March 15, 2010. Zimmerman wrote on the application he wanted to go on the ride-along to "solidify chances of my career in law enforcement."

Wednesday afternoon, the jury learned from Anthony Gorgone, a crime lab analyst, that Trayvon's DNA was not found on Zimmerman's gun. Gorgone, who works for the Florida Department of Law Enforcement, took the stand a day after another state witness testified that Trayvon's fingerprints were not found on the gun. In arguments to the jury, state attorneys have continued to stress those points.

Meanwhile, Gorgone testified that George Zimmerman's DNA was found on Trayvon Martin's shirt that was worn under Trayvon's hoodie but not on the hoodie itself.

Trayvon's DNA was on Zimmerman's jacket --including on the bottom right cuff--but not on Zimmerman's undershirt.

Gorgone added that DNA can be degraded by mold, humidity and other environmental impacts. Trayvon's hoodie and the shirt he wore under it were packaged in plastic bags while still wet. That isn't recommended and when Gorgone received the clothing, the teen's hoodie smelled of mold and both items were still wet.

Gorgone said he may have gotten more DNA results had the clothes been packaged differently.

State prosecutors are expected to rest their case Friday when the trial resumes.